NO参与玉米幼苗对盐胁迫的应答

以玉米幼苗为材料,研究盐胁迫下其內源NO含量、NR和NOS活性的变化;NOS专一性抑制剂L-NAME和NR非专一性抑制剂NaN3对玉米幼苗內源NO含量的影响;利用激光共聚焦显微技术观测盐胁迫下玉米幼苗根部NO含量的变化及其分布特点。结果表明,盐胁迫下玉米幼苗根尖和叶片中NO含量有猝发现象,NOS活性也随之显著提高,NR活性则显著降低;L-NAME或NaN3均可降低盐胁迫所引起的玉米幼苗NO水平的增加,L-NAME对NO含量的影响比NaN3更显著。推测,NO参与玉米幼苗对盐胁迫的应答,NOS途径是盐胁迫下玉米幼苗內源NO合成的主要途径。     

Proteomic Analysis of Trypanosoma cruzi Response to Ionizing Radiation Stress

Trypanosoma cruzi, the causative agent of Chagas disease, is extremely resistant to ionizing radiation, enduring up to 1.5 kGy of gamma rays. Ionizing radiation can damage the DNA molecule both directly, resulting in double-strand breaks, and indirectly, as a consequence of reactive oxygen species production. After a dose of 500 Gy of gamma rays, the parasite genome is fragmented, but the chromosomal bands are restored within 48 hours. Under such conditions, cell growth arrests for up to 120 hours and the parasites resume normal growth after this period. To better understand the parasite response to ionizing radiation, we analyzed the proteome of irradiated (4, 24, and 96 hours after irradiation) and non-irradiated T. cruzi using two-dimensional differential gel electrophoresis followed by mass spectrometry for protein identification. A total of 543 spots were found to be differentially expressed, from which 215 were identified. These identified protein spots represent different isoforms of only 53 proteins. We observed a tendency for overexpression of proteins with molecular weights below predicted, indicating that these may be processed, yielding shorter polypeptides. The presence of shorter protein isoforms after irradiation suggests the occurrence of post-translational modifications and/or processing in response to gamma radiation stress. Our results also indicate that active translation is essential for the recovery of parasites from ionizing radiation damage. This study therefore reveals the peculiar response of T. cruzi to ionizing radiation, raising questions about how this organism can change its protein expression to survive such a harmful stress.     

基于蛋白质组学对螺旋藻砷胁迫响应机制的研究

通过研究螺旋藻(Spirulina sp.)在砷离子胁迫下的蛋白质组变化,从蛋白质表达水平解释螺旋藻对砷离子胁迫的响应机理。螺旋藻经过不同浓度砷离子胁迫7 d后,提取蛋白质进行凝胶电泳,并对差异蛋白进行质谱分析。结果表明螺旋藻在2.0 ppm砷酸盐中暴露10 min光合放氧速率降低27.3%,培养24 h后细胞内的金属硫蛋白、叶绿素、类胡萝卜素及藻胆蛋白相对含量均明显降低。蛋白组学共鉴定出75个差异蛋白,其中26个显著上调,49个呈现下调。这些差异蛋白表明砷离子主要通过破坏螺旋藻光合色素蛋白,干扰电子传递过程,导致能量合成受损,使得依赖光合作用产生能量进行的跨膜运动、蛋白质合成等相关过程受到影响;同时,活性氧清除与防御相关蛋白呈现上调,螺旋藻细胞内抗氧化系统被激活。     

小麦耐盐突变体盐胁迫下的蛋白质组分析

首次采用双向电泳的方法分析1％NaCl胁迫72h的一对小麦耐盐(RH8706-49)及敏盐突变体(H8706-34)的蛋白质组。经过MALDI-TOF分析和数据库检索发现两者在H^ -ATP酶β亚基、谷氨酰胺合成酶前体、OEC33和RuBP羧化酶小亚基等5个候选蛋白存在质或量的差异。这5种蛋白均为叶绿体蛋白,它们很可能在盐胁迫下对维持叶绿体及整个细胞的功能起到重要作用。     

Proteomic Analysis of Salt Stress Responses in Rice Shoot

To gain a better understanding of the mechanism of rice (Oryza sativa L.) in response to salt stress, we performed a proteomics analysis of rice in response to 250 mM NaCl treatment using shoots of 3-day-old nascent seedlings. The changes of protein patterns were monitored with two-dimensional gel electrophoresis. Of 57 protein spots showing changes in abundance in response to salt stress, 52 were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The identified proteins were classified into eight functional categories. Several novel salt stress-responsive proteins, including protein synthesis inhibitor I, photosystem II stability/assembly factor HCF136, trigger factor-like protein and cycloartenol-C24-methyltransferase are upregulated upon salt stress. In order to figure out the different and similar molecular mechanism among salt and other stresses, regulation of some salt responsive proteins under other abiotic stress (cold and dehydration) and abscisic acid application was also analyzed. The possible molecular mechanism of rice seedlings in response to salinity and other stresses were discussed.     

蛋白质组学在细菌应激反应研究中的应用

当外部生存环境发生变化时,细菌会在短时间内发生应激反应。利用双向凝胶电泳技术结合生物质谱鉴定的方法对细菌蛋白表达谱变化进行研究,是细菌转录谱变化研究的深入和扩展,是细菌应激反应研究中的新热点。综述了蛋白质组学在细菌应激反应研究中的应用现状和存在问题。     

烟草幼苗响应弱光胁迫的转录组分析

为了研究烟草幼苗对弱光胁迫反应的分子机制,以'云烟87'为材料,构建全光照和弱光处理条件下大十字期烟苗cDNA文库,利用Illumina测序技术进行转录组测序,筛选差异表达基因.结果表明:借助RNA-seq技术共筛选到2 956个DEGs,其中弱光相对于全光照表达上调的DEGs有691个,表达下调的DEGs为2 265...     

Proteomic Analysis of Seedling Roots of Two Maize Inbred Lines That Differ Significantly in the Salt Stress Response

Salinity is a major abiotic stress that limits plant productivity and quality throughout the world. Roots are the sites of salt uptake. To better understand salt stress responses in maize, we performed a comparative proteomic analysis of seedling roots from the salt-tolerant genotype F63 and the salt-sensitive genotype F35 under 160 mM NaCl treatment for 2 days. Under salinity conditions, the shoot fresh weight and relative water content were significantly higher in F63 than in F35, while the osmotic potential was significantly lower and the reduction of the K⁺/Na⁺ ratio was significantly less pronounced in F63 than in F35. Using an iTRAQ approach, twenty-eight proteins showed more than 2.0- fold changes in abundance and were regarded as salt-responsive proteins. Among them, twenty-two were specifically regulated in F63 but remained constant in F35. These proteins were mainly involved in signal processing, water conservation, protein synthesis and biotic cross-tolerance, and could be the major contributors to the tolerant genotype of F63. Functional analysis of a salt-responsive protein was performed in yeast as a case study to confirm the salt-related functions of detected proteins. Taken together, the results of this study may be helpful for further elucidating salt tolerance mechanisms in maize.     

The Comparatively Proteomic Analysis in Response to Cold Stress in Cassava Plantlets

Cassava (Manihot esculenta Crantz) is a tropical root crop and sensitive to low temperature. However, it is poorly to know how cassava can modify its metabolism and growth to adapt to cold stress. An investigation aimed at a better understanding of cold-tolerant mechanism of cassava plantlets was carried out with the approaches of physiology and proteomics in the present study. The principal component analysis of seven physiological characteristics showed that electrolyte leakage (EL), chlorophyll content, and malondialdehyde (MDA) may be the most important physiological indexes for determining cold-resistant abilities of cassava. The genome-wide proteomic analysis showed that 20 differential proteins had the same patterns in the apical expanded leaves of cassava SC8 and Col1046. They were mainly related to photosynthesis, carbon metabolism and energy metabolism, defense, protein synthesis, amino acid metabolism, signal transduction, structure, detoxifying and antioxidant, chaperones, and DNA-binding proteins, in which 40 % were related with photosynthesis. The remarkable variation in photosynthetic activity and expression level of peroxiredoxin is closely linked with expression levels of proteomic profiles. Moreover, analysis of differentially expressed proteins under cold stress is an important step toward further elucidation of mechanisms of cold stress resistance.     

Accumulation of myo -Inositol in Actinidia Seedlings Subjected to Salt Stress

Seedlings of kiwifruit (Actinidia deliciosa (A. Chev.) C. F.Liang et A. R. Ferguson vardeliciosa ) and A. arguta (Sieb.et Zucc.) Planch. ex Miq. grown in hydroponic nutrient solutionswith elevated salt (MgSO₄and KCl) concentrations showed visiblesigns of stress at salt concentrations of 50 m M and above.The polyol myo -inositol accumulated in leaf tissue when thesalt was added to 15 m M or more, with increases being similarin the two species. The increase in concentration of myo -inositolwas approximately linear with rising salt. At any given saltconcentration an increase in myo -inositol was linear with timefrom application of salt.myo -Inositol concentrations increasedwithin the first 24 h of salt treatment, and declined againas quickly once the stress was removed. Sucrose also increasedwith salt stress, accumulating only once plants showed physicalsigns of stress. Accumulation of myo -inositol was negativelycorrelated to fructose and glucose. Copyright 1999 Annals ofBotany Company Actinidia arguta, Actinidia deliciosa, kiwifruit, leaf tissue, myo -inositol, salt stress, sucrose.     

Weak Microwave Can Enhance Tolerance of Wheat Seedlings to Salt Stress

The aim of our investigation was to determine the effect of microwave pretreatment of wheat seeds on the tolerance of seedlings to salt stress. Selected parameters (for example, plant growth and biochemical parameters related to oxidative status) were measured. The results showed that microwave pretreatments for 5, 10, 15, or 20 s resulted in an increase in root length and shoot height in seedlings, with 10- and 15-s treatments giving the greatest effect. Salt stress, produced by treatment with 200 mM NaCl, reduced the length and fresh weight of shoots and roots, enhanced the leaf concentrations of malondialdehyde (MDA) and oxidized glutathione (GSSG), indicators of oxidative stress, while decreasing the activities of nitric oxide synthase (NOS), catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), and glutathione reductase (GR). Furthermore, the salt treatment reduced the concentration of nitric oxide (NO) and glutathione (GSH) in the shoots. However, treatments of seeds with microwave radiation followed by salt stress restored all of these parameters close to those in non-salt-treated seedlings. The results indicate that application of a suitable dose of microwave radiation to seeds can enhance tolerance to salt stress in wheat seedlings.     

Proteomic Analysis Identifies Ribosome Reduction as an Effective Proteotoxic Stress Response

Stress responses are adaptive cellular programs that identify and mitigate potentially dangerous threats. Misfolded proteins are a ubiquitous and clinically relevant stress. Trivalent metalloids, such as arsenic, have been proposed to cause protein misfolding. Using tandem mass tag-based mass spectrometry, we show that trivalent arsenic results in widespread reorganization of the cell from an anabolic to a catabolic state. Both major pathways of protein degradation, the proteasome and autophagy, show increased abundance of pathway components and increased functional output, and are required for survival. Remarkably, cells also showed a down-regulation of ribosomes at the protein level. That this represented an adaptive response and not an adverse toxic effect was indicated by enhanced survival of ribosome mutants after arsenic exposure. These results suggest that a major source of toxicity of trivalent arsenic derives from misfolding of newly synthesized proteins and identifies ribosome reduction as a rapid, effective, and reversible proteotoxic stress response.     

NaCI胁迫对盐芥和拟南芥光合作用的影响

本研究检测了与盐芥(Ghellungiella halophila)和拟南芥(Arabidopsis thaliana)光合作用相关的叶绿素、净光合速率(photosynthetic rate,Pn)、气孔导度(stomatal conductance,Gs)、胞间隙CO2浓度以及叶绿素荧光参数等指标,观察到随着NaCl浓度逐渐增加,盐芥的叶绿素a／b值(Chl a／Chl b)、类胡萝卜素／总叶绿素值(Car／Chl)显著高于拟南芥,且二比值变化幅度较小并保持较高水平。盐胁迫下拟南芥净光合速率下降、气孔导度下降和胞间CO2浓度减小。气孔因素是引起拟南芥光合能力下降的主要因素。叶绿素荧光参数的变化表明,50-200 mmol·L-1NaCl降低拟南芥叶绿体对光能的吸收能力,而且降低叶绿体的光化学活性,使电子传递速率和光能转化效率大幅度下降,造成光能转化为化学能的过程受阻,进一步加剧了光合放氧和碳同化能力的降低。而50-200 mmol·L-1NaCl胁迫没有使盐芥的光合作用受到不良影响。